Downloads for website via a repository

Instead of using the 'Downloads' part of bitbucket for downloads, it makes sense to use a repository instead.

This way syncing with the website can be done more easily, and it also makes it easier for the buildbots. The 'Downloads' section does not have an API currently, which makes dealing with them hard with scripts.

Also, some minor points are that this allows people to submit downloads via a pull requests, and it also provides a history and MD5 sum for the downloads.

@Paul Craven : There's a script which generates html from the JavaScript, and json. Yeah, a cron job of sorts. Except it watches for changes on the file system and does the business.

@anatoly techtonik : wheels sound usable definitely. I believe there's still problems with the wheel format for linux distros, but it works at least for windows and Mac OS X. On OS X, this may involve moving the Framework dependencies inside of the pygame package. Rather than having them install into separate locations. I'm thinking this is the right approach for the .dmg OS X installers too. Here's the wheel docs... http://pythonwheels.com/ Issue See #222 for tracking wheels.